In these cases writs of certiorari were granted (295 U.S. 726, 55 S.Ct. 833, 79 L.Ed. 1677; 295 U.S. 726, 55 S.Ct. 835, 79 L.Ed. 1678) to resolve conflicts with respect to the scope and alleged infringement of claims 1 to 6, 8, 10, 14, and 15 of the Gullborg patent, No. 1,307,734. In No. 23 the Circuit Court of Appeals, while holding the claims valid, so construed them as to exculpate the accused devices from the charge of contributory infringement. In No. 31 the Circuit Court of Appeals gave the claims a broader construction and adjudged that the petitioners were guilty of contributory infringement.
The subject of the patent is a device for lubricating metal bearings, particularly those of automobiles. It has occasioned much litigation. Before the date of Gullborg's invention grease cups were used for bearing lubrication. The cup was connected with the bearing by a tube and oil or grease was forced through the tube into the bearing by screwing down a cap or plunger which was part of the cup. It became common to substitute, in place of the grease cup, a tubular fitting and to force grease through the fitting by means of a 'gun' consisting of a compression chamber and an attached hose, the latter coupled to the fitting by a screw thread or bayonet coupling. In the case of the bayonet coupler the fitting had lugs or pins and the coupler device had slots which engaged such lugs or pins to form a tight union. The grease would then be forced from the chamber of the gun into the bearing by the use of a plunger or pump. In some of the prior art appliances the aperture of the fitting was kept closed when greasing was not being done by a ball or capsule held against the opening of the fitting by a spring. This closure is opened, during the greasing operation, by the pressure of the grease. Gullborg conceived the idea of a fitting in which, instead of pins or lugs set on either side, there should be a pin running directly through the tube and extending out on either side. He used that portion of the pin which bisected the tube as the base of a spring to hold in place a metal ball which closed the aperture of the fitting. This invention was novel in the respect that while others had similarly closed the aperture of the fitting none had employed the pin both to form the lugs for engaging the slots of the coupler and to form the base of the spring supporting the ball closure. For this invention he applied for and obtained a patent, No. 1,307,733, which is not here in suit. Recognizing that when a bayonet coupler is secured to the pin fitting, and the grease is forced through the fitting into the bearing under great pressure, upon uncoupling the gun from the fitting some grease will remain around the end of the fitting and the orifice of the coupler which is not only useless but likely to soil the clothing of the operator or others using the machine, and litter the place where the greasing is done, Gullborg set about to devise a means for eliminating this residuum of grease. He conceived the idea of placing a movable perforated cup-shaped disk or washer in the barrel of the coupler held by a spring against the orifice of the coupler. The intended operation of his device was that when the coupler had been fastened over the pin fitting the spring should press the washer against the ball in the pin fitting so that the tube in the fitting would be open to receive the grease and, upon aplication of pressure to the grease, the washer would thereby be firmly pressed against the opening of the pin fitting, thus causing a tight union and preventing exudation of grease. His specif cation asserts that the invention makes possible the injection of grease under very high pressure. The design of the bayonet slots is such that, in uncoupling, the coupling member of the gun will at first be moved slightly forward on the pin fitting thus backing up the perforated washer in the bore of the coupler. As the two parts are then drawn apart by the retraction of the coupler, the cup-shaped washer will be forced forward by the spring. This will cause a vacuum behind the washer and the air rushing in through the perforation in the washer will draw with it any grease which would otherwise adhere about the orifices of the fitting and the coupling.